1. Field of the Invention
The present invention is in the field of illumination devices and, more specifically, light emitting diode (LED)-based illumination devices.
2. Description of the Related Art
Most lighting applications utilize incandescent or gas-filled bulbs, particularly lighting applications that require more than a low level of illumination. Incandescent bulbs typically do not have long operating lifetimes and thus require frequent replacement. Gas-filled tubes, such as fluorescent or neon tubes, may have longer lifetimes, but operate using dangerously high voltages, are relatively expensive, and include hazardous materials such as mercury. Further, both bulbs and gas-filled tubes consume substantial amounts of power.
In contrast, light emitting diodes (LEDs) are relatively inexpensive, operate at low voltage, and have long operating lifetimes. Additionally, LEDs consume relatively little power, are compact, and do not include toxic substances. These attributes make LEDs particularly desirable and well suited for many applications.
Although it is known that the brightness of the light emitted by an LED can be increased by increasing the electrical current supplied to the LED, increased current also increases the junction temperature of the LED. Excessive heat reduces the efficiency and lifetime of the LED. Advances in LED technology have brought increasingly bright LEDs. However, such increased brightness is accompanied by increased heat-generation.